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B6db references: 90165457

type Journal Article
authors Hoare, K.; Datta, K.
title Characteristics of L-alanine:4,5-dioxovaleric acid transaminase: an alternate pathway of heme biosynthesis in yeast
journal Arch Biochem Biophys
ui 90165457
year (1990)
volume 277
number 1
pages 122-9.
keywords Candida albicans/*enzymology
abstract The present study reports for the first time the presence of the enzyme L-alanine:4,5-dioxovaleric acid transaminase (EC, which catalyzes the irreversible synthesis of 5-aminolevulinic acid in three strains of yeast: Candida albicans 3100, Saccharomyces cerevisiae 3059, and S. cerevisiae S288C. The enzyme was predominantly present in the cytosol and was purified from C. albicans 3100 by about 200-fold with an overall yield of 23% to apparent homogeneity. The purification procedure involved heat treatment, followed by affinity chromatography on L-alanine-Sepharose CL-4B, ion-exchange chromatography on DEAE- cellulose DE-52, and chromatography on hydroxyapatite. As judged by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the enzyme appeared to be a monomeric protein of relative molecular mass 59,000. The enzyme activity was stimulated by pyridoxal phosphate and was optimally active at 60 degrees C. The purified enzyme had an isoelectric point of 4.7 and a pH optimum of 7.2 Km values of the enzyme for L-alanine, pyridoxal phosphate, and 4,5- dioxovaleric acid were 2.8 X 10(-7), 5.0 X 10(-7), and 1.05 X 10(-5) M, respectively. The Vmax of the enzymatic reaction was 5 X 10(-6) mol/mg/h. Antibody raised against the purified yeast L-alanine:4,5- dioxovaleric acid transaminase did not cross-react with the same enzyme from rat liver and kidney.
last changed 2002/11/12 16:17

B6db references